29MHz trans Atlantic DX...

[K0ZAK]

Results from my testing with M0DTS this morning to Baltimore, Maryland, USA while the signals were fading. Was starting to get good clustering around the dots, but not quite enough to detect any valid data. I have a strong local radio station presenting an image just above our test frequency so it is likely causing issues with the decoding. I have a broadcast band filter on the way, so hopefully that will help.

11-21-2022 Test with M0DTS_2.jpg (346.91 KiB) Viewed 5286 times

Currently using a an RTLSDR dongle and SDRAngel. Will try hooking up my Pluto with a upconverter to see if it receives any better.

John Kozak; K0ZAK

[M0DTS]

Hi John,

Unfortunately it does not look like you were getting my signal, under the pink marker on the spectrum you should have seen the 'noise' band of my signal.
The constellation dots are false, possibly related to the centre spike but not 100% sure there.

The main thing i notice is the gain setting on the top left for the rtlsdr, it's right down at zero, this will not help.
The gain on the rtlsdr usually needs to be up quite high to get reasonable sensitivity.
I know you have issues with broadcast breakthrough but that filter on it's way should help.

Have a play with SSB signals and adjusting the gain level, you maybe surprised how much it comes up!

Rob


Edit: here's an example of my rtsldr receiving my local signal in SDRAnglel.
The signal is clearly visible under the pink band, and of course on the spectrum.
You can usually remove the centre spike with the 'DC' button on the rtlsdr settings.

[K0ZAK]

Rob,
I noticed the gain being reduced after we finished. I had saved all the settings with the gain up, however sometimes they don't stick, and I didn't notice. It boils down to me not knowing the software very well. I'm trying to set up the Pluto & ham it up upconverter on SDRAngel now, so should be able to try both receivers next time (with the gain turned up)

John Kozak: K0ZAK

[radiogareth]

Now transmitting 18ks, 29.150, listening on 29MHz Zello if anyone can see my signal.
Gareth

[K0ZAK]

partial success with Rob's video this morning.

11-22-2022 Test with M0DTS.jpg (268.56 KiB) Viewed 5067 times

[K0ZAK]

A few video updates but no motion yet with the weak signals today

11-22-2022 Test with M0DTS_2.jpg (275.26 KiB) Viewed 5063 times

[G1LPS Terry]

Well done Gents a picture over the atlantic

[M0DTS]

Well sort of,

This could have happened on SSTV with better quality... but it's a start
Hope for some flowing video next!

Rob

[G4GUO]

I think it will be a while before I can test out the Wideband HF modem software I am working on.

My preference would be to apply for an experimental permit to try some tests on 5 MHz, but I
suspect that would be a total waste of time, judging by my last attempt at getting an experimental permit.

- Charles

[radiogareth]

Transmitting from 1:45 GMT 18ks test card with clock. Better propagation than Tuesday, fingers crossed. About 55 watts into a Vertical with a little gain (0.5dB...its a 'Slim Jim' made from 450 ohm ribbon cable).
Gareth